Contact structure for electrical circuit controllers



13, 1941- F. F. HUMPHREYS ETAL 2,263,090

CONTACT STRUCTURE FOR ELECTRICAL CIRCUIT CONTROLLERS Filed Sept. 1, 1957 7 1z\ 8 (Q) 3 a 3 5 E 5 z 5 5 2 J 1 inoavzim: JJ-aizmrzaffimprq:

J/Zcf A. fZg'asezz Patented Nov. 18, 1941 UNI E D STAT E S PATEN T O FF I CE CONT-ACT STRUCTUREFORELECTRICAL CIRCUIT CONTROLLERS Original application September 1, 1937, Serial No. 161,956, now Patent No. 2,233,532, dated March Divided and this application August 3, 1940, Serial No. 350,670

(CLZGO-lfifi) 4 Claims.

ture for electrical circuit controllers that is adapted to'handle the flow of electrical currents with uniform contact pressure, and without destructive arcing. Furthermore, this contact structure is so arranged that the current carrying parts thereof which are subject to wear and deterioration under heavy service conditions, can be quickly replaced without demounting the device. The above and other advantageous features of the invention will hereinafter more fully appear from the following description with reference to the accompanying drawing in which:

l is a view in front elevation of a circuit controllerembodying the invention.

Fig. 2 is a View in side elevation of the parts shown in Fig. 1.

Fig. 3 is a fragmentary view of one of the contact arm assemblies shown in Fig. l.

Figs. 4 and 5 are perspective views, illustrating the contact arm and contact structure, separated from each other.

Fig. 6 is a sectional view along the line 6-6 of Fig. 3, on an enlarged scale.

Like reference characters refer to like parts in the different figures.

Referring first to Figs. 1 and 2, the invention is shown. for purposes of illustration, as being embodied in a circuit controller of the relay type, the essential elements of which comprise an insulating base I carrying U-shaped core 2, one leg of which is surrounded by an energizing winding 3. A magnetic armature 4 is pivotally supported on the lower end of the other core leg and carries a pair of arms 5 suitably insulated from the armature 4 at 6. Each arm 5 carries a pair of contacts I projecting from opposite sides of an arm 5, which contacts I constitute an assembly separately removable from the arm, as will be hereinafter described.

In the normal deenergized condition of the winding 3 the armature 4 occupies the position of Fig. 2 with the arm contacts 1 in engagement with a pair of back contacts 8 mounted on a yoke 9 of insulating material. The armature 4 provides an extension III, and a spring II cooperating with this extension I0 tends to pull the armature 4 downwardly about its pivot and maintain contacts.8"with .apredetermined pressure dependentupon the adjustment of the spring I I.

.Upon'energization of the winding 3, the armature 4 'will :be turned upwardly about its pivot to .move'the arm contacts I into engagement with the pair of front stationary contacts I2 mounted onthe base I. A relay of the type described thus far is known as a front and back contact relay, wherein the flow of current through the back contacts 8 is maintained for one outside circuit condition as long as the winding 3 remains deenergized, while flow of current between the front contacts I2 is maintained for another circuit condition, as long as the winding 3 is-energized.

As previously pointed out, a pair of arm contacts '1 are constructed as a unit for mounting on an arm and this construction is best shown in Figs. 3, 4 and 6. The contacts I are connected by a cross bar I3 providing an opening through which freely extends a pin I4 providing heads I5 at its ends. Washers I6 are mounted on the pin I4 on either side of the bar I3 and a coil springII surrounds the free portionof the pin I4 between its head I5 and each washer I6. Thus each washer I6 is yieldingly maintained in engagement with the bar I3 so that normally in the assembled contact unit, the Washers I6 extend in parallel relation.

As best shown in Fig. 5, each arm 5 provides a slot I8 the sides of which are parallel near the base of the arm. The free end of the arm 5 is enlarged as indicated at I9 and the slot I8 widens to provide curved portions 20 only slightly less in diameter than the contacts I and washers I6. When it is desired to position an assembled contact unit, such as shown in Fig. 4, in an arm 5, the extremities of the arm 5 are flexed, as indicated in dotted lines in Fig. 5, to permit the insertion of the contacts I between the opened sides of the slot portions. This results in the washers I6 engaging opposite sides of the arm 5 and the springs I1 tend to yieldingly maintain the washers I6 in such engagement. Therefore, the entire contact assembly is in effect floating at the end of the arm 5, so that each contact I may seek its own adjustment with the front or back contact I2 or 6. Obviously when the contacts I become worn, the entire assembly can be readily removed from an arm 5 by flexing it so as to release the washers I6, and a new contact unit substituted, without in any way disturbing any other parts of the device or necessitating the arm contacts "I in engagement with the back removal from its mounting.

As previously pointed out, the spring ll serves to yieldingly maintain the contacts I in engagement with back contacts 8 and the degree of contact pressure can be readily controlled by a convenient adjustment of the spring tension. For this purpose, one end of the spring H is anchored by threading its end coils around a fixed screw 2|. The opposite end of the spring H is similarly engaged with threads on a stud 22 extending through an opening in the armature extension ID. The stud 22 carries a lock nut 23 between the extension l and a guide 24, and an adjusting nut 25 beyond the extension l0. By turning the adjusting nut 25 in one direction or the other, the tension of the spring II can be increased or decreased to control the contact pressure. Any setting of the spring ll thus obtained can be maintained by turning the lock nut 23 up against the extension In to cause the end of the nut 25 to be received within an angular seat 26 provided in the extension Ill. Thus the lock nut 23 will effectively prevent any backing off of the adjusting nut 25 following an adjustment of the spring and which might otherwise occur as a result of repeated operations of the armature. For any given setting of the spring H, the contacts 1 will adjust themselves to the back contacts 8, by reason of the floating support of the contacts 1 at the end of each arm 5.

We claim:

1. In a device of the class described, a movably mounted arm providing openings near its free end, with portions of said arm being flexible with respect to each other, a pair of contacts having portions of larger diameter than said arm openings, and joined together as a unit by reduced portions of such size as to be receivable in said openings by fiexure of said arm portions to admit said contacts, and means for yieldingly maintaining said contact unit in position on said arm, with said contacts extending beyond said openings on opposite sides.

2. In a device of the class described, a movably mounted arm providing a slot and openings near its free end, and a contact unit comprising spaced contacts having portions of larger diameter than said arm openings and joined together by a bridging member, with springs extending from opposite sides of said bridging member, flexure of portions of said arm on opposite sides of said slot permitting the insertion of said contact unit within said arm openings, with said springs yieldingly maintaining said contact portions beyond said openings.

3. In a device of the class described, a movably mounted arm providing a slot and openings near its free end, with portions of said arm on opposite sides of said slot being flexible with respect to each other, a contact unit comprising 1 space-d contacts joined together by a bridging member of less width than said arm slot, with said contacts having portions of larger diameter than said arm openings, flexure of portions of said arm on opposite sides of said slot permitting the insertion of said contact unit within said arm openings, with said contact portions of larger diameter disposed beyond said arm on opposite sides thereof.

4. In a device of the class described, a movably mounted arm providing a slot and openings near its free end, with portions of said arm on opposite sides of said slot being flexible with respect to each other, a contact unit comprising spaced contacts joined together by a bridging member of less width than said arm slot, with said contacts having portions of larger diameter than said arm openings, and springs carried by said bridging member on opposite sides thereof and bearing on washers of larger diameter than said arm openings, flexure of said arm on opposite sides of said slot permitting the insertion of the contact unit within said arm openings, with said springs yieldingly maintaining said washers in engagement with opposite sides of said arm to yieldingly maintain the contact portions of larger diameter beyond said arm openings.

FERDINAND F. HUMPHREYS. TELLEF A. TERJESEN. 

